Roll stand for a rolling mill



A ril 14, 1970 D. GRUBE 3,

' ROLL STAND FOR A ROLLING MILL Filed Sept. 27, 1967 2 Sheets-Sheet 1Fig 7 N es April 14, 1970 D. GRUBE ROLL STAND FOR A ROLLING MILL 2Sheeis-Shee; 2

Filed Sept. 27, 1967 United States Patent O 3,505,849 ROLL STAND FOR AROLLING MILL Dietrich Grube, Ratingen-Tiefenbroich, Germany, as-

signor to Schloemann Aktiengesellschaft, Dusseldorf, Germany, a companyof Germany Filed Sept. 27, 1967, Ser. No. 670,991 Claims priority,application Germany, Oct. 1, 1966, Sch 39,613 Int. Cl. B21b 29/00 US.Cl. 72-215 4 Claims ABSTRACT OF THE DISCLOSURE A roll stand with theworking rolls guided along arcuate paths and having swinging backingsegments with arcuate section bearing surfaces for backing the workingrolls.

The present invention relates to a roll stand for a rolling mill, havingco-operating working rolls rotatably mounted in swinging supports forguiding the working rolls along respective arcuate paths, the workingrolls being braced against bending during operation.

Roll stands of this kind are known in which the work ing rolls aredisplaceable in the swinging supports in a direction which is radial tothe axis of swing, and are supported by a stationary guide path or trackduring the working operation, the swinging supports being driven by forinstance crank drives.

In such a roll stand, a radial guide way is required for the workingrolls, for two reasons; firstly, the guide way must bear any non-radialload caused by internal shear and elongation stresses within thematerial being worked, during deformation, such non-radial loads beingparticularly high due to the low speed of operation in such roll stands;secondly, the guide way must bear the non-radial loads caused by thebrutal operation of the roll stand and the high energy loss arising fromthe inertial forces of the to-and-fro movement of the material beingrolled. Such a roll stand has a complex structure and is relativelyexpensive.

In a second known roll stand, two working rolls of small diameter aremounted on carriages so that they can be displaced relative to eachother at right angles to the machine direction, i.e. the direction oftravel of the material being rolled, the rolls being driven byfrictional engagement (or by like arrangement) with eccentric segmentswhich in turn are driven by means of racksand toothed sectors.

The spacing between the centres of rotation of the eccentric segmentscannot be altered because this spacing is established by the toothedsector driving gear; thus the spacing between the axes of the Workingrolls cannot be changed in this manner in order to take up wear or allowfor changes in the section of the material being rolled. A furtherdisadvantage is that a slideaway system is required for the carriagesand the entire roll housing undergoes a reciprocatory motion inoperation.

As a development of roll stands in which the axes of swing arethemselves rotated about a further axis and which has the disadvantagethat the direction of rolling is opposed to the direction of travel ofthe material being rolled, roll stands are known in which the workingrolls are rotatably mounted in swinging supports which are driven bymeans of suitable mechanisms (for instance jointed or articulatedlinkages) with the working rolls having a small diameter and bracedagainst bending by means of backing rolls also mounted in the swingingsupports.

Roll stands of this latter type are not economical for all workingloads; the greater the bending stress acting on the working rolls, thegreater the size the backing rolls should have; however, the size of thebacking rolls is lim- Patented Apr. 14, 1970 ited on the one hand by thedistance of the working rolls from the axis of swing and on the otherhand by the loss of power (which is proportional to the square of theradii of the backing rolls) caused by the inertial losses as the backingrolls reverse their direction of rotation twice during each swing of theswinging supports.

In addition, it is often necessary to replace the working rollsfrequently due to the high frictional loading on the working rollscaused by the transmission of the forces to the backing rolls necessaryto change the direction of rotation of the backing rolls.

According to the present invention, there is provided a roll stand for arolling mill, having cooperating Working rolls rotatably mounted inswinging supports for guiding the working rolls along respective arcuatepaths, and swinging backing segments mounted for swinging movement aboutthe same axes as the respective swinging supports and'having arcuatesection bearing faces against which the respective working rolls bearand roll along in operation, thereby to brace the working rolls againstbending."

The roll stand of this invention can reduce the power loss in the milland reduce the wear of the working rolls which is caused by inertialforces due to to-and-fro movement of the workpiece; in addition, theroll stand of this inventipn can be adjusted to allow for differentsections of workpiece, and can be designed for any particular rollingload, the radius of the backing segments corresponding to the requiredresistance against bending stress; in this manner, the backing segmentscan have a minimum moment of inertia and can allow for a smaller rollstand housing. Furthermore, the roll stand of this invention can bearranged to be suitable for brutal operation.

The backing segments may be driven and a mechanical connection (i.e.friction or gear) provided to cause the working rolls to roll along thebearing surfaces of the backing segments and move along their arcuateworking paths. This can reduce the frictional forces on the workingrolls and avoid the necessity for driving the backing segments by meansof the working rolls.

In order to prevent the working rolls from slipping on the backingsegments or on the material being rolled, at least one gear Wheel may befixed to each working roll so that it meshes both with an external gearsegment fixed to the respective backing segment and with a stationaryinternal gear segment, the radius of the gear wheel pitch circle beingthe same as the radius of the working roll, and the radius of theexternal gear segment pitch circle being the same as the radius of thebacking segment bearing surface.

The roll stand of the invention can be mounted in series with at leastone other roll stand in a rolling mill in order to roll the material toits final size in one pass through the mill at a predeterminedthroughput speed; the material may for instance issue from a continuouscasting plant. In order to balance or partly balance the inertial forcesof the swinging supports, adjacent stands may be out of phase in therolling cycle.

The. invention will be further described, by way of example, withreference to the accompanying drawings, in which:

FIGURE 1 is a vertical section through a roll stand in accordance withthe invention, along the line I-I of FIGURE 2; and

FIGURE 2 is an elevation of a rolling mill in accordance with theinvention, incorporating two roll stands generally as shown in FIGURE 1.

For convenience, the same references are used for the left-hand rollstand in FIGURE 2 as for the right-hand roll stand, but the referencesfor the left-hand roll stand are primed. Though the section line forFIGURE 1 is 3 taken along the plane I-I of FIGURE 2, the references arenot shown primed in FIGURE 1.

As shown in FIGURE 1, the two working rolls 1 are rotatably mounted inswinging supports 2 which are pivoted to spindles 3 mounted on a rollhousing 4.

In addition, backing segments 5 are pivoted to the spindles 3 and arearranged to be driven in an oscillatory manner by reciprocating links 6,7; the links 6, 7 may be driven by a crank drive (as shown in FIGURE 2)or by any other suitable manner, for instance an articulated drivesystem.

Gear wheels 8 are mounted at each end of each working roll 1 usingsuitable connection flanges, and these gear wheels 8 mesh both with anexternal gear segment 9 fixed to the respective backing segment 5 andwith a stationary internal gear segment 9a, fixed to the roll stand. Thepitch circles of the gear wheels 8 and of the gear segments 9 arearranged (in the manner indicated above) such that the working rolls 1roll along the arcuate bearing surfaces of the backing segments 5, andare driven by the movement of the backing segments 5.

Though not shown, means (such as an eccentric mounting) may be providedfor varying the spacing between the power of spindles 3.

In operation, the backing segments 5 are swung in unison, causing theworking rolls 1 and the swinging supports 2 to swing at the same time.The material W is advanced into the roll gap when the swinging supports2 have reached their outermost (i.e. upstream) dead centre position, theamount of advance of the material W depending on the smoothness of thematerial W and on the acceptable load during each stroke. The material Wis held fast (for instance by the rolls 24, 25 shown in FIGURE 2) whilstthe working rolls I carry out their rolling action.

The mill of FIGURE 2 has a driving system 10 including twocontra-rotating gears 11 and spindles 12, 13. The cranks 14, 16 for thelinks 7', 6 are at an angle of 90 to the cranks 15, 17 for the links 7,6 so that the two roll stands are 90 out of phase.

In operation, the material W is advanced by the pinch rolls 24, 25 whenthe working rolls 1 of the right-hand stand are in their outermost deadcentre position. In the subsequent movement of the working parts, theworking rolls 1 will move in the opposite direction to the working rolls1' whilst the working rolls 1' smooth the surface of the material W.

The phase difierence between the roll stands makes the load on thedriving system 10 more even. Furthermore, the spacing of the waves whichare formed in the surface of the material W by the working rolls 1 ofthe right-hand stand is halved in the left-hand stand and the surface ofthe rolled material W is made more uniform.

The roll stand or mill of the invention may be used for rolling ferrousor non-ferrous metals.

Iclaim:

1. A roll stand for a rolling mill, having co-operating Working rollsrotatably mounted in swinging supports, for guiding the working rollsalong respective arcuate paths, swinging backing segments mounted forswinging movement about the same axes as the respective swingingsupports and having arcuate section bearing surfaces against which therespective working rolls bear and roll along in operation, thereby tobrace the working rolls against bending, and means for driving thearcuate movement of the backing segments and the arcuate and rotarymovements of the working rolls, the driving means including a mechanicaldriving connection between the working rolls and the backing segments toconstrain the working rolls to roll along the bearing surfaces of thebacking segments during the arcuate movement of the backing segments.

2. A rolling mill having in series at least two roll stands as claimedin claim 1, a driving mechanism, and mechanical transmissions connectingeach stand to the driving mechanism with adjacent stands out of phase inthe working cycle.

3. A rolling mill as claimed in claim 2, having only two said standswith the stands out of phase.

4. A roll stand as claimed in claim 1, comprising an external gearsegment fixed to each respective backing segment, the radius of theexternal gear segment pitch circle being the same as the radius of therespective backing segment bearing surface, at least one gear wheelfixed to each working roll means and meshing with the respectiveexternal gear segment, the radius of the gear wheel pitch circle beingthe same as the radius of the respective working roll means, and astationary internal gear segment meshing with each gear wheel.

References Cited UNITED STATES PATENTS 2,085,729 7/1937 Coe 72-2142,125,686 8/1938 Norton 72-215 3,103,139 9/ 1963 Saxl 72215 FOREIGNPATENTS 48,131 10/1937 France.

LOWELL A. LARSON, Primary Examiner US. Cl. X.R. 72241

